Hitori's Syndrome is a running gag in Nansei series and in Nansei Dev Team. It's named after Hitori and it's used to indicate, when there's a character with puppet/minion/pet/pupil/creation who...
- ...is less known than it's puppet/minion/pet/pupil/creation;
- ...apears twice less times than it's puppet/minion/pet/pupil/creation;
- ...debuts after it's puppet/minion/pet/pupil/creation and stays in the series for less longer;
- ...cannot appear without it's puppet/minion/pet/pupil/creation in any projets;
- ...had less design variation than it's puppet/minion/pet/pupil/creation;
- ...is less important for the project's story than it's puppet/minion/pet/pupil/creation;
It appeared first in Autumnal Mythology with Hitori of course, who not only has appeared together with it's summoner -Fuan Satsujin-, not only he apeared again in the same project without her, not only he is more important to the story tha she is, not only he has apeared in more project since, not only Fuan never appeared in any project wthout him, but he also has more sprite's/designs variaty. Since his apear this gag appears on every possible occasion, like with:
- Ragoni (they debuted before their creator - Fayette Brightsight)
- Pupa-chan (she appeared more often than her controller -Hagane Zero- and she had more designs)
- Hitori (not only again for Fuan, but also for Eria Kanrei)
- Every other creation of Eria Kanrei for her.
- Panti no Kodomo (if Mariela Kyooju is really her mentor/teacher)
- Hiyake Hebi kind of (she appears twice in the series, compared to her more powerful parents and big sister, she also was a final boss. midboss, while her parents appeared at lower stages)
- Majutsu (for Hitori in Demons in Wonderland, except for the "appear in more project's" rule)
- Kuromuro & Ippiki for Michio Usanori.
- Chusokarashi no Manaato for Sonohoka Wyra and her other creators.